For a study, the researchers sought to determine if patients who got spinal region corticosteroid injections (CSI) had a higher chance of getting influenza than matched controls. A retrospective cohort analysis was conducted. Adults (n=9,196) who got a spinal CSI (epidural, facet, sacroiliac, paravertebral block) during influenza seasons from 2000 to 2020 were matched 1:1 to controls who did not get a spinal CSI. Compared with matched controls, the primary outcome was the likelihood of influenza diagnosis in spinal CSI patients. Influenza diagnostic odds were assessed in predetermined subgroup analyses based on vaccination status and injection site. From 2000 to 2020, an institutional database was searched to find patients who got spinal CSI throughout influenza season (September 1 to April 30). Patients were matched to controls without spinal CSI during the designated influenza season based on age, sex, and influenza vaccination status. The diagnosis of influenza was determined using International Classification of Disease codes, and the data were analyzed using multiple logistic regression adjusted for comorbidities linked to higher influenza risk. A total of 9,196 people (mean age 60.8 years, 60.4% female) had their spines scanned and matched to a control group.
In comparison with matched controls, spinal CSI patients had no higher risk of influenza (OR 1.13, [95% CI, 0.86–1.48]). There were no higher odds of influenza for spinal CSI patients based on immunization status (unvaccinated or vaccinated) or spinal injection location when subgroups were evaluated (epidural or non-epidural). CSI in the spinal area was not linked to an increased risk of influenza or decreased vaccination effectiveness. Given the injections’ analgesic and functional restoration effects, this was reassuring. In the period of the COVID-19 pandemic, assessing the risk of viral infection related to spinal CSI was especially important, and further research was needed to address the issue.